What are the strongest springs?

Compression springs manufactured from high-quality chrome silicon or chrome vanadium wire are the strongest springs. These steel alloys provide a chemical composition, surface property and tensile strength that when combined with spring size deliver outstandingly strong performance levels.

Do springs weaken under compression?

Springs do weaken under compression, over time. This is called relaxation and creep. Relaxation is when the stress level of the spring decreases over time at a constant deflection and thus loses force. Creep is when the spring loses length (increased deflection) at a constant force. This is time-dependent and can be predicted by our team.

How do I order a bespoke compression spring?

Speak to our experts on 01726 861444 or email heavysprings@lesjoforsab.com . We will talk you through every step of the process to ensure we maximise your spring application's success.

Heavy Duty Extension Spring Manufacturers

Expert engineering

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Custom heavy duty extension springs

Leading manufacturer of heavy-duty and custom extension springs for various industries.

We are experts in heavy-duty Extension Spring Manufacturing. We design, engineer and manufacture millions every year for custom specifications.

As expert heavy duty extension spring manufacturers, our springs operate throughout a whole host of heavy extension spring applications across multiple industries including construction, robotics, lifting equipment, agriculture, elevators and heavy plant machinery as well as speciality equipment.

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Bespoke extension springs specific for your application

Our teams are expert extension spring manufacturers offering hot coiling and cold coiling manufacturing capabilities across some of the most advanced spring technologies in the industry.

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What are heavy-duty extension springs?

Heavy duty extension springs are tightly wound coils that allow for an outside force to create tension through an end fitting or loop, using this energy to pull components back together when reverting back to their original extension spring shape.

Our division specialises in the heavy extension spring which is the largest of the extension spring range.

As heavy duty extension springs suppliers we design and manufacture heavy duty extension springs UK wide and across the globe for a wealth of diverse industries and applications.

How do extension springs work?

Extension or tension springs are similar to compression springs but with one distinct difference, the load direction is reversed – a tension (pulling) force, instead of a compression (pushing) force, causes the deflection via an end fitting.

The extension spring works as a link or an attachment between two components, drawing them together when another force separates them. An extension spring, for example, would be used on a trampoline to secure the matt to the frame but more significantly provide the energy required through its tension to give the trampoline its bounce. A high rated extension spring would give additional energy and bounce compared to a lower rated extension spring.

Find more about spring terminology.

Tension Spring characteristic infographic showing spring stretching

Read how extension springs work

Manufacturing extension springs

Our hot coiling facilities can manufacture extension springs up to 65mm wire diameter with our cold coiling starting at 3mm wire diameter.

CNC Coiling

Quality Assurance - ISO 14001, ISO 45001 and ISO 9001 certified

Engineered for maximum strength and durability

Contact Spring manufacturing process

Types of extension springs and fittings

Extension springs with hook ends or loops formed from the spring body, with an equal diameter as the spring body, are the most common and cost-effective extension coil spring end design for customers. There are a number of different types of end loops and hooks available as options for expansion springs, as well as a wide range of other mechanical attachment possibilities, including:

Extension Spring With German Loops

Extension Spring With Half Hooks

Extension Spring With English Loop

Extension Spring With Extended Hooks

Extension Spring With Side Hooks

Extension Spring With Side Loops

Extension Spring With Screw Plugs

Extension Spring With Crew Shackles

Extension springs with round-end hook and extension springs with a V-hook are our most popular range but below shows the options available including extension springs with extended eyes, loops and swivel hooks. Each can be applied to suit the application required.

Ordering custom springs made easy

At Lesjofors, we make ordering custom springs a seamless process. Our team of experts is here to guide you through every step, ensuring you get the perfect springs for your specific needs.

Discuss your requirements with our team

To achieve the best results in developing your extension springs, our engineers ask a multitude of questions to ensure the extension spring performance achieves maximum success for the customer.

Custom spring design and manufacturing

Our experienced engineers will design and manufacture custom springs according to your specifications, ensuring a high-quality and reliable performance. The extension spring design often goes through many cycles to guarantee the right design for the right purpose.

Stringent quality control and testing

This comprehensive review process, including meticulous attention to detail at every step, reinforces our commitment to delivering high-quality springs recognised in our ISO 9001, 14001 and 45001 certifications.

HOW TO ORDER CUSTOM SPRINGS

Lesjöfors Heavy Springs for reliable and heavy-duty performance

Our extension springs are designed to deliver exceptional performance and durability, making them the premium choice for heavy-duty applications.

Design & development

Allocated team of experts ensuring that the final product meets all requirements and specifications.

Prototypes & samples

Creating a precision spring solution that enables you to test the requirements of your product before going into full production.

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Heavy duty extension spring materials

We hold the largest stock of chrome silicon in the world and work with carbon steels, low and high alloyed steels which enables our engineers to source the right material for the right application and work environment of your extension spring.

When considering industrial extension springs we need to evaluate the extension spring material for chemical composition, surface properties, tensile strength and wire diameter.

Our material scientists are leaders in their field and are on hand to consult with our engineers on the properties of all our metals.

Carbon Spring Steel

Chrome Silicon

Chrome Vanadium

Stainless Steel

Nickel Alloys

Titanium Alloys

Copper Alloys

SEE ALL TYPES OF MATERIALS

Looking for custom extension springs?

With a 170-year manufacturing legacy and state-of-the-art production and commercial infrastructure, we deliver a competitive environment dedicated to quality, accuracy and customer satisfaction, guaranteeing Lesjöfors Heavy Springs as the premium partner for your heavy duty spring solutions.

Enquire now

Does your business require a different custom spring?

Lesjöfors Heavy Springs offers a consultancy service. Our teams are available to discuss any engineering and technical issues regarding heavy spring specifications. Explore our Heavy Duty Compression Spring and Torsion Spring pages.

Heavy duty extension spring FAQs

What is the purpose of an extension spring?

An extension spring is designed to absorb and store energy by resisting a pulling force. Its primary purpose is to return to its original length when the force causing the extension is removed.

What are benefits of extension springs?

Extension springs offer several advantages, including the ability to absorb and store significant energy, making them ideal for applications requiring controlled tension and resistance. They are versatile and customisable in terms of length, diameter, and material, ensuring optimal performance for specific needs.

What materials are used for extension springs?

Extension springs are manufactured from a variety of materials to meet different application needs. High-carbon steel is commonly used for its strength and durability in general applications. Stainless steel provides excellent corrosion resistance, making it suitable for environments exposed to moisture. Phosphor bronze offers good corrosion resistance and electrical conductivity, ideal for specific industrial and electrical uses. Nickel alloys, such as Inconel, are chosen for their high-temperature resistance and strength in extreme conditions. Additionally, music wire, a type of high-carbon steel wire, is favoured for its high tensile strength and durability in demanding applications.

What is the lead time?

The lead time for our extension springs varies depending on the complexity of the design and the quantity required. We strive to deliver orders within the agreed-upon timeframe.

Do you offer samples & prototypes?

Yes, we can provide samples of our extension springs for testing and evaluation. Contact us to discuss your sample requirements.

Still have questions?

Feel free to reach out to us.

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